Electric discharge lamp



March 21, 1950 R. L. BREADNER ET AL ELECTRIC DISCHARGE LAMP Filed Feb. 25, 1946 S2 HDS mmm CJ @Dm e V.l .OVUJ O C mme A @mun m .Tuur T Ira enh.; @may E b generally straight lengths of tubing.

Patented n. zi, 195ov y UNITED 'isTATEs PATENT OFFICE ELECTRIC mscnAaGuLAMr Robert Leonard Breadner, AKenton, Henry Grainger Jenkins, Pinner, and .Charles Henry Simms, Twickenham, England, assignors to General Electric Company, a corporation of New York Application Februar-y 25, 194s, serial No. 650,067

f In Great Britain December 21, 1944 Section 1, Public Law 690, August 8, 1946 Patent expires December 21, 1964 11 Claims. (Cl. 176-122) 2 According to the present invention a discharge lamp of the type specified has a discharge path in the form of a two-start spiral or helix. The electrodes may be' arranged in the extremities of the fore applicable to hot cathode lamps having their envelopes coated internally with fluorescent powder, in which the discharge passes through mercury vapour usually admixed with a few millimetres pressure of a rare gas such as argon. Such lamps are now of -great importance as light sources.

The dimensions of these fluorescent lamps,I

which are usually but not necessarily of circular -cross-section, may vary, for example, from a few inches to several feet in length and from 1/" to 2" in mean diameter. by mass production methods and are, therefore, Other shapes. such as grids, spirals, etc., have often been proposed but such shapes do not lend themselves readily to mass production methods and can be obtained, in general, only by manipulation by skilled craftsmen. The operation becomes progressively more difiicult to perform as the4 y caps which may need to be very accurately spaced 'apart to ilt into a housing with pre-set sockets for the supply of electric power. Also large linear sources are diiilcult to deal with optically and where a fitting is used this is large and costly in relation to the wattage of the lamp. For these reasons fluorescent lamps have been virtually ruled out for street lighting where the excellent spectral characteristics of their light might be used to great advantage.

The invention is concerned with discharge lamps of the type in which compactness is secured by giving the discharge path between two electrodes a spiral orl like shape and in which the discharge path is a channel formed between two vitreous components sealed together, one or both of the components having one or more upstanding ridges which separate adjacent parts of the discharge path from one another.

discharge path which are adjacent to one another but preferably they are accommodated in tubulations sealed to the extremities of the discharge path.

In any case by giving the discharge path the form of-a two-start spiral. the electrodes and means for making electrical connection therewith can readily be located clear of the lamp surface through which the greater part of the light emission takes place. Two such two-start spiral dis- They are usually made,

charge paths maybe provided with the turns of the spirals interleaved with one another and each discharge path may be provided with a different' gas or vapour lling and/or different fluorescent coatings whereby a desired colour combination can be obtained.

The invention will be described with reference to the accompanying drawing wherein Fig. 1 shows somewhat diagrammatically `one formof discharge passage according to the invention; Fig. 2 is a side view in section along the line 2-2 of Fig. 1; and Fig. 3 is a somewhat diagrammatic plan view of a modification.

In Figs. 1 and 2 of the drawing one spiral discharge passage runs from I0 to the centre and the other from the centre to I I. 'Ihese passages are bounded by two spiral ridges I2 and I3 interleaved with one another. The ridges I2 and I3 may be lformed by moulding, pressing or by the application of a strip or the like of glass to a flat glass disc I8 and fusing the strip to the disc by heating. The outer ends o f the ridges are turned inwards at I4 and I5 and joined to the adjacent ridge in order to close the passages. The ridges may be provided on both of the components or one component may be as shown in Fig. 1 of the drawing and a plain glass disc I9 (Fig. 2) may constitute the second component. In any case the components are fused together along the crests of the ridges and in'this Way a two-start spiral passage closed excepting for the two ends is provided. At the two ends of the passage tubulations I6 and I1 are preferably sealed through one component I8, electrodes 2D and 2| are arranged on pinches -22 in these tubulations, the inner wall surfaces of the passage are if desired coated with fluorescent powder 23, the passage is evacuated, and filled with a suitable gas or vapour and sealed oil.

It will be seen that with the formv of discharge passage described the electrodes and the means azionarei 3 for making electrical connection therewith can be located' outside the greater part of the surface glass disc-shaped walls through which light is emitted. With a single,4

start spiraL'on the other hand, an electrode is required at or near the centre of the lamp or alternatively a tabulation connected with the -centrai region oi.' the lamp must be provided.

Instead oi locating the tubulations I6 and Il as shown they may be arranged alongside oi one another, or at diametrically opposite points or in any other convenient position.

An envelope constructed in the form above de scribed may be made to provide two independentl discharge paths each having the form of a twostart spiral or helix and the two paths being sealed from one another and provided with a different gas illling or luminescent powder or both and independent pairs of electrodes; this construction involves suitably modifying the shape o! the channels produced in one or both components. In one example of a lamp with two discharge paths. both contain a illlingl of neon and in one fluorescent zinc silicate may be used as the luminescent powder whilst in the other the luminescent powder may be calcium tungstate as described in British patent specification No. 457,486. The neon with the zinc silicate gives a yellow light and the neon with calcium tungstate a pink light, the mixed light from the combination being a very warm white colour. Alternatively either of the above discharge paths may be used in combination with a `discharge path having a mercury vapour illing and using a suitable fluorescent powder such as a mixture oi' zinc beryllium silicate and magnesium tungstate for example. Such a structure is shown in Fig. 3 wherein electrodes 24, 25 are located at the ends of a discharge path 26, while electrodes 21, 28 are located at the ends of another discharge path 29.

We claim:

1. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed glass disc-shaped walls separated by a pair 0I transverse parallel interleaved spiraled glass partitions joined to and between said walls and extending from outer peripheral extremities to a point at the center of the disc-shaped walls where their inner extremities terminate in adjacent spaced relationship whereby to jointly -dene a continuous spiral passage bounded by the adjacent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, an ionizable medium in Said passage. and electrodes arranged at the outer ends only of said passage.

2. An electric discharge lamp comprising glass bulb having a pair oispaced and opposed glass disc-shaped walls separated by a pair of transverse parallel interleaved spiraled glass partitions joined to and .between said walls and ex separated by two pairs of transverse parallel interleavedspiraled glass partitions joined to and between said walls and each extending from outer peripheral extremities to a point at thecenter oi the disc-shaped walls where their` inner extremities terminatein adjacent spaced relationship whereby to jointly deline a continuous'spiral passage bounded by the adjacent convolutions oi said partitions and extending irom the outer extremity thereof tothe inner extremities and thence-back to another point at the outer extremity, an ionizable medium in each ci said passages, and electrodes arranged at the outer ends only oi each of said passages.

4. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed glass disc-shaped walls separated by t-wo pairs of transverse parallel interleaved spiraled glass partitions joined to and between said walls and each extending from outer peripheral extremities to a point at the center of the disc-shaped Walls where their inner extremities terminate in adjacent spaced relationship whereby to jointly deiine a continuous spiral passage bounded by the adjacent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, a different ionizable medium in each of said passages, and electrodes arranged at the outer ends only of each of said passages.

5. An electric discharge lamp comprising a glass bulb having a pair oi spaced and opposed glass disc-shaped Walls separated by a pair of transverse parallel interleaved spiraled glass partitions joined to and between said walls and extending from outer peripheral extremities to a point at the center of the disc-shaped walls where their inner extremities terminate in adjacent spaced relationship whereby to jointly denne a Y continuous spiral passage bounded by the adjacent convolutions oi' said partitions and extending from the outer extremity thereof to the inner extremities and thence Vbaci: to another point at the outer extremity, an ionizable medium in said passage, fluorescent material on the inside of the walls of'saicl passage, and electrodes arranged at the outer ends only of said passage.

6. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed glass disc-shaped walls separated by two pairs of transverse parallel interleaved spiraled glass partitions joined to and between said walls and each Vextending from outer peripheral extremities to a point at the center of the disc-shaped walls where their inner extremities terminate in adjacent spaced relationship whereby to jointly deine a continuous spiral passage bounded by the adjatending from outer peripheral extremities to a A cent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, an ionizable medium in each oi' said passages, uorescent material on the inside oi the walls oi' said passages, and electrodes arranged at the outer ends only of each of said passages.

' '7. An electric discharge lamp comprising a. glass bulb having a pair of spaced and opposed glass said passage, tubes sealed to the ends only oi said passage, and an electrode in each of said tubes. 3. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed disc-shaped walls separated by two pairs of transverse parallel interleaved spiraled glass partitions joined to and between said walls and each extending from outer peripheral extremities to a point at the center of the disc-shaped walls where their inner extremities terminate in adjacent spaced ous spiral passage bounded by the adjacent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, a diilerent ionizable medium in each of said passages, a fluorescent material lon the inside wall of at least one ofsaid passages, and electrodes arranged at the outer ends only of each of said passages.

8. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed glass disc-shaped walls separated by two pairs of transverse parallel interleaved spiraled glass partitions joined to and between said walls and each extending i'rom outer peripheral extremities to a point at the center of the disc-shaped walls Where their inner extremities terminate in adjacent spaced relationship whereby to jointly denne a continuous spiral passage bounded by the adjacent convolutions nf said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, a diierent ionizable medium' in each of said passages, a diierent iiuorescent material in each of said passages, and electrodes arranged at the outer ends only of each of said passages.

9. An electric lamp comprising a sealed ilat bulb having a substantially flat bottom wall and a substantially ilat transparent cover plate parallei to the bottom wall, convolute partitions in said ends only of said passages, lead-iris for the electrodes, and a suitable gas illling said bulb and providing a discharge path between opposing electrodes serving as a source of illumination.

10. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed walls and a pair of transverse parallel interleaved spiraled partitions between said walls extending from outer extremities to a. point where their inner extremities terminate in adjacent spaced relationship whereby to provide a continuous spiral passage bounded by the adjacent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, the outer end of each of said partitions being turned inward and joined to an adjacent portion of the other partition so that the outermost convolutions of the partitions themselvesv constitute the outer boundaries of said passage, an ionizable medium in said passage, and electrodes arranged at the outer ends of said passage. 11. An electric discharge lamp comprising a glass bulb having a pair of spaced and opposed glass disc-shaped walls separated by a pair of transverse parallel interleaved spiraled glass partitions joined to and between said Walls and extending from outer peripheral extremities to a point at the center of the disc-shaped walls where their inner extremities terminate in adjacent spaced relationship whereby to jointly define a continuous spiral passage bounded by the adjacent convolutions of said partitions and extending from the outer extremity thereof to the inner extremities and thence back to another point at the outer extremity, the outer end of each of said partitions being turned inw-ard and joined to an adjacent portion of the other partition so that the outermost convolutions of the partitions themselves constitute the outer boundaries of said passage, an ionizable medium in said passage, and electrodes arranged at the outer ends only of said passage.

ROBERT LEONARD BREADNER.

HENRY GRAINGER JENKINS.

CHARLES HENRY SIMMS.

, REFERENCES CITED The following references are of record in the file of this patent: v

UNITED STATES PATENTS Number Name Date 1,813,759 Peters July 7, 1931 1,870,147 Smally Aug. 2, 1932 1,935,423 Wayringer Nov. 14, 1933 1,961,735 Braun June 5, 1934 1,981,903 Cadieux NOV. 27, 1934 1,984,215 Hotchner s Dec. 11, 1934 2,009,375 Ford July 23, 1935 2,042,316 Johnson May 26, 1936 2,205,672 Sawyer June 25, 1940 2,255,431 Marden Sept. 9, 1941 2,269,819 Isenberg Jan. 13, 1942 2,405,518 Polevitzky Aug. 6, 1946 2,406,146 Holmes Aug. 20, 1946 IiORlilICiN PATENTS4 Number Country Date 513,715 Great Britain Oct. 19, 1939 

